DE102008011165A1 - Sensor arrangement, in particular for an occupant protection system of a motor vehicle - Google Patents

Abstract

Sensor arrangement, in particular for an occupant protection system of a motor vehicle, comprising - a first group of sensors (10, 12), with which a first group of state parameters can be detected, which are jointly usable by a downstream decision unit for the detection of a first event, - a first on the input side with at least one sensor (12) of the first sensor group coupled digital unit (20) which processes their supplied sensor output signals and provides for forwarding to the decision unit as digital values, wherein - a second group of sensors (14, 16, 18), with a second group of state parameters can be detected which can be used jointly by the downstream decision unit to detect a second event; a second digital unit coupled to at least one sensor (16, 18) of the second sensor group and processing its supplied sensor output signals and to the distance providing at least one sensor (10) of the first sensor group to the second digital unit (22) and at least one sensor (14) of the second sensor group to the first digital unit (20); and 20, 22) on the output side with a first and a second node (28, 30) corresponding to the respectively supplied digital values on a first and a second output line (32, 34) ...

Description

Field of the invention

• – eine erste Gruppe von Sensoren, mit denen eine erste Gruppe von Zustandsparametern erfassbar sind, welche von einer nachgeschalteten Entscheidungseinheit gemeinsam zur Erkennung eines ersten Ereignisses nutzbar sind,
• – eine erste, eingangsseitig mit Sensoren der ersten Sensorgruppe gekoppelte Digitaleinheit, die ihr zugeführte Sensor-Ausgangssignale verarbeitet und zur Weiterleitung an die Entscheidungseinheit als Digitalwerte bereitstellt.

The invention relates to a sensor arrangement, in particular for an occupant protection system of a motor vehicle

• A first group of sensors, with which a first group of state parameters can be detected, which are jointly usable by a downstream decision unit for the detection of a first event,
• A first digital unit coupled on the input side with sensors of the first sensor group, which processes its supplied sensor output signals and provides them as digital values for forwarding to the decision unit.

State of the art

such Arrangements commonly known as so-called. Crash detection systems. As a rule, two of the sensor group are perpendicular to one another, typically longitudinally and transversely of the Vehicle-oriented acceleration sensors includes the excessive Capture acceleration components of the vehicle and to a digital unit, for example, the digitization of analog sensor output signals serves, forwards. The digitized data is then sent to a controller forwarded, which is a decision on possibly too gripping occupant protection measures, such as the tightening of straps or the deployment of airbags, meets.

A more advanced form of accident sensors is from the DE 10 2006 009 372 A1 known. There, a rollover or rollover detection system for a motor vehicle is disclosed. Here, too, the system consists of a group of sensors, in particular of a transverse acceleration sensor which detects accelerations along the vehicle transverse axis and a vertical acceleration sensor which detects vertical accelerations of the motor vehicle. In addition, a rotation rate sensor is provided which detects rotations of the vehicle about its longitudinal axis. The output signals of the acceleration sensors are supplied to a digital unit where they are subjected to digital filtering and further processing and output on a common output line to a control unit. In the known system, the data of the rotation rate sensor are fed directly to the control unit. Again, the controller decides on the basis of the data supplied to him about any occupant protection measures.

From the DE 102 35 567 A1 a rollover sensor system is known which manages without gyroscope sensor and makes a decision as to whether a rollover event exists solely on the basis of a measured vertical acceleration in connection with a longitudinal or lateral acceleration of the vehicle. However, this system must be considered sub-optimal for reliable differentiation from pure crash events.

While a pure crash sensor technology in modern vehicles as standard equipment often the roll-over sensor is an additional option, which is purchased by the customer. Typically, the customer will by installing an additional module comprising a additional sensor group and an additional Digital unit, suited. Next, the algorithmics in one Control unit which processes the data of both sensor groups, be adjusted accordingly. The latter constitutes an essential Intervention is easier because the algorithms for detection Crash events is comparatively easy compared to detection two different events (crash and rollover), the must be distinguished reliably, in each case the adequate occupant protection measures to be able to take.

A particularly critical situation may arise if due to a Component failure does not address the information of a sensor group to the Control device to be forwarded. Due to the complex algorithmics It can happen that then the sensor data of the remaining Sensor group are misinterpreted and the overall performance of the Systems is worse than the one only on the detection Crash Events System. As particularly failure critical have the digital units, typically realized by Microcontrollers, viewed as a "bottleneck" in the Represent data flow.

The while the above difficulties could be avoided, by upgrading the sensor system for the Detecting two different events, the sensor data only about a common microcontroller would be sent. This would enable the controller to Failure of this part due to the lack of any data reliable to recognize. As a result, however, this would be a total failure of the protection system, which is undesirable is. Also, in order to maintain the upgradability, for each basic version, d. H. only crash sensors, a multi-channel Microcontrollers are used in the case of upgrading to rollover sensor would have to be rewired consuming. This is disadvantageous in terms of manufacturing technology.

task

It is the object of the present invention tion to provide a sensor system for a motor vehicle, which can be easily upgraded for the detection of an additional event and which also offers a high level of functional reliability in case of part failure.

Presentation of the invention

• – eine zweite Gruppe von Sensoren, mit denen eine zweite Gruppe von Zustandsparametern erfassbar sind, welche von der nachgeschalteten Entscheidungseinheit gemeinsam zur Erkennung eines zweiten Ereignisses nutzbar sind,
• – eine zweite, eingangsseitig mit Sensoren der zweiten Sensorgruppe gekoppelte Digitaleinheit, die ihr zugeführte Sensor-Ausgangssignale verarbeitet und zur Weiterleitung an die Entscheidungseinheit als Digitalwerte bereitstellt,

wobei

• – wenigstens ein Sensor der ersten Sensorgruppe mit der zweiten Digitaleinheit und wenigstens ein Sensor der zweiten Sensorgruppe mit der ersten Digitaleinheit gekoppelt ist, und
• – die Digitaleinheiten ausgangsseitig mit einem ersten und einem zweiten Knoten, die ihnen jeweils zugeführten Digitalwerte entsprechend auf eine erste und eine zweite Ausgangsleitung zusammenführen, derart gekoppelt sind, dass der erste Knoten die den Sensoren der ersten Sensorgruppe entsprechenden Digitalwerte auf der ersten Ausgangsleitung und der zweite Knoten die den Sensoren der zweiten Sensorgruppe entsprechenden Digitalwerte auf der zweiten Ausgangsleitung zusammenführt.

This object is achieved in conjunction with the features of the preamble of claim 1

• A second group of sensors, with which a second group of state parameters can be detected, which are jointly usable by the downstream decision unit for the detection of a second event,
• A second digital unit which is coupled on the input side with sensors of the second sensor group and processes its supplied sensor output signals and makes them available as digital values for forwarding to the decision unit,

in which

• At least one sensor of the first sensor group is coupled to the second digital unit and at least one sensor of the second sensor group is coupled to the first digital unit, and
• - The digital units output side with a first and a second node, which merge their respective supplied digital values according to a first and a second output line are coupled such that the first node corresponding to the sensors of the first sensor group digital values on the first output line and the second Node merges the digital values corresponding to the sensors of the second sensor group on the second output line.

core The invention is an entanglement of the sensor data the bottle necks formed by the digital units and a rearrangement of the sensor data prior to their delivery to the control unit. Thus, according to the invention thematically, d. H. related to one of the events to be recognized, ordered sensor data split and different digital units fed. After the desired processing in the digital units, for example, a digitization of may include analog sensor data, the data will be back in their summarized thematic order and each one on each one to be recognized event associated line to the control unit aufcodiert. The controller thus receives event-specific Inputs all relevant to the assessment of the event State parameters. Nevertheless, a failure of a digital unit despite their key position as a "bottleneck" not to a total failure of the flow of information to one of the events. Much more the status parameters of both events are transmitted incompletely, which, however, by clever choice of entanglement by Use of redundant information at least partially compensated can be.

at A preferred embodiment provides that the first sensor group a longitudinal acceleration sensor for high acceleration components along the longitudinal axis of the motor vehicle and a lateral acceleration sensor for high acceleration components along the transverse axis of the motor vehicle includes. This is a well-known crash sensor.

Prefers the second sensor group comprises a lateral acceleration sensor for low acceleration components along the transverse axis of the Motor vehicle, a vertical acceleration sensor for low acceleration components along the vertical axis of the Motor vehicle and a rotation rate sensor for rotations of the motor vehicle about an axis perpendicular to its vertical axis, This preferably corresponds to the structure of a typical rollover sensor system.

In such a design of the sensor system, in which typically the crash sensor system, the base sensor and the rollover sensor system represent the optional additional sensor, the sensor of the second sensor group coupled to the first digital unit is preferably its yaw rate sensor. This means that the data of the rotation rate sensor, which in principle - albeit suboptimal - alone may be sufficient to detect a rollover event, are removed from their thematic order. Advantageously, in return, the coupled with the second digital unit sensor of the first sensor group whose lateral acceleration sensor. This means that in the crash sensor system, the data of the lateral acceleration sensor are removed from their thematic order. Thus, the data of the lateral acceleration sensor of the crash sensor are entangled with the data of the rotation rate sensor of the rollover sensor and the other digital unit for processing, in particular digitization supplied. After being processed in the digital unit, all sensor data are returned to their original thematic order via the two nodes and fed to the controller on the two event-specific output lines. This has significant advantages in case of damage to one of the digital units. Falls z. B. the first digital unit, so the longitudinal acceleration data of the crash sensor are transmitted to the control unit on the first output line, the data of the rotation rate sensor and on the second output line. This allows most types of crash events and rollover events to be detected, albeit suboptimal. Conversely, if the second digital unit fails on the first output line, the crossover and vertical acceleration data of the roll sensor and on the second output line transmit the lateral acceleration data of the crash sensor to the controller. Again, this is sufficient to detect - albeit suboptimal - most crash and rollover events.

The Coding of the data on the event-specific output lines preferably takes place as a periodic sequence of the respective Node supplied digital values. This is conveniently a the control unit known protocol, d. H. a predefined one Timing used. In this way, the controller the incoming data due to their position in the periodic Identify sequence. When coding a case-specific Prioritization of the data. So, for example proved that the data of the vertical acceleration sensor and the lateral acceleration sensor of the second sensor group, d. H. preferably the rollover sensor, less time are critical as the data of the rotation rate sensor or the data the lateral and the longitudinal acceleration sensor of the first Sensor group, d. H. preferably the crash sensor. Therefore is at a favorable development of the invention provided that the lateral acceleration sensor and the vertical acceleration sensor the second sensor group corresponding digital values within the periodic sequence positioned in the same time window and alternating are encoded in successive periods. This means with other words, that in the preferred embodiment during a coding period, the data of the lateral acceleration sensor the rollover sensor and in the following period the data of the vertical acceleration sensor of the rollover sensor be coded on the same position or phase of the period. The remaining Data that is more time-critical, as explained above transmitted with each period.

Which one special processing the sensor data in the digital units can be subjected by the skilled person with regard to the specific field of application be largely freely chosen. A typical processing is the digitization of analogue sensor signals. alternative or additionally, in a further development of the invention also a threshold comparison with a predetermined threshold be made. In this embodiment can then be provided that the sent on the event-specific output lines Data are 1-bit values that merely tell the controller that the corresponding sensor is above or below has detected the associated threshold value. In other embodiments instead, you can also set values in larger ones Digitization depth transmitted to the controller for further processing become. Threshold comparisons may be made in this embodiment be made in the control unit.

Brief description of the drawings

Further Features and advantages of the present invention will become apparent the following special description and the drawings.

It demonstrate:

1 a schematic block diagram of a sensor system according to the invention;

2 : a diagram of the preferred timing of the sensor system of 1

Detailed description more concrete embodiments

1 shows a schematic block diagram of a particularly preferred embodiment of a sensor system according to the invention. The system consists of two modular component groups, each comprising a sensor group, a microcontroller and a node. The first component group essentially corresponds to a known crash sensor system. The second component group essentially corresponds to a known rollover sensor system. The present invention is evident in the advantageous combination of both component groups.

The first sensor group includes a lateral acceleration sensor 10 for high accelerations along the transverse axis of the vehicle and a longitudinal acceleration sensor 12 for high accelerations along the longitudinal axis of the vehicle. The second sensor group comprises a rotation rate sensor 14 for detecting a rotation of the vehicle about its longitudinal axis, a lateral acceleration sensor 16 for low accelerations along the transverse axis of the vehicle and a vertical acceleration sensor 18 for detecting low accelerations along the vertical axis of the vehicle. The sensors of the two groups are arranged thematically, ie those sensors that can be used together to detect an event are grouped together in a sensor group. This can be expressed in the arrangement of all sensors of a sensor group in a common housing. In the present embodiment, the sensors are included 10 and 12 the first sensor group to a crash sensor while the sensors 14 . 16 and 18 belong to the second sensor group to a rollover sensor.

Downstream of the sensor groups are a first digital unit, preferably a first microcontroller 20 and a second digital unit, before preferably a second microcontroller 22 , In the microcontrollers 20 . 22 each three functional units are realized, namely a multiplexer 202 respectively. 222 , an analog / digital converter 204 respectively. 224 as well as a demultiplexer 206 respectively. 226 , The mentioned functional units may be in software, in hardware or in a combination of software and hardware in the digital units 20 respectively. 22 be realized. The inputs of the first multiplexer 202 be with the sensor data of the longitudinal acceleration sensor 12 the crash sensor and the sensor data of the rotation rate sensor 14 the rollover sensor charged. The inputs of the second multiplexer 222 be with the sensor data of the lateral and vertical acceleration sensors 16 . 18 the rollover sensor and the sensor data of the lateral acceleration sensor 10 the crash sensor charged. In one of a central clock 24 predetermined clock are the at the inputs of the multiplexer 202 . 222 applied, analog sensor data to an A / D converter 204 respectively. 224 where they are digitized at the required digitization depth. From the respective downstream demultiplexer 206 respectively. 226 The digitized sensor data are sent to outputs of the microcontroller 20 respectively. 22 directed.

The microcontrollers 20 . 22 Downstream are a first node 28 and a second node 30 representing the digital data applied to the node inputs on an associated output line 32 respectively. 34 output. The output lines 32 . 34 are connected to a control unit, not shown, in which a further processing and in particular a decision about to be taken occupant protection measures. The knots 28 . 30 can be realized as simple amplifiers or as summers, but it should be noted that no true data summation takes place; rather, the demultiplexers 206 . 226 so clocked that at a time window within a coding period at each node 28 . 30 only one value is present while the other node inputs are connected to high-resistance microcontroller outputs.

At the entrances of the nodes 28 . 30 the thematic orders of the input-side sensor groups are restored. Ie. at the entrances of the first node 28 are the transverse and longitudinal acceleration data of the sensors 10 and 12 the first sensor group, while at the inputs of the second node 30 the lateral and vertical acceleration data as well as the rotation rate data of the sensors 14 . 16 . 18 abut the second sensor group. These data are periodically in constant time windows on the event-specific output lines according to a predetermined protocol 32 . 34 coded and fed to event-specific inputs of the control unit, not shown. In other words, on the first output line 32 transmit the state parameters that are optimally utilized to detect a crash event and the second output line 34 those state parameters are transmitted which are optimally used to detect a rollover event.

One recognizes in 1 clearly the double data entanglement of the present invention. Thus, in particular, the data of the lateral acceleration sensor 10 the crash sensor and the data of the rotation rate sensor 14 the rollover sensor removed from their thematic context and processed together with the data of the remaining sensors of the other sensor group in a microcontroller. After processing, they are re-interleaved and the offloaded data becomes event-specific nodes 28 . 30 returned and coded on event-specific lines. This causes that in case of failure of a microcontroller 20 . 22 none of the output lines 32 . 34 is completely "dead", but that on both lines 32 . 34 Data are passed to the control unit, which are still sufficient to detect both crash and rollover events and in particular to distinguish both types of events. In the embodiment shown, in case of failure of the first microcontroller 20 on the first output line 32 the data of the lateral acceleration sensor 10 the crash sensor and on the second output line 34 the data of the lateral and vertical acceleration sensors 16 . 18 transmitted the rollover sensor. In case of failure of the second microcontroller 22 be on the first output line 32 the data of the longitudinal acceleration sensor 12 the crash sensor and on the second output line 34 the data of the rotation rate sensor 14 transmitted the rollover sensor.

The sensor system of the present invention is characterized by high modularity. Thus, it is possible, for example, in a basic version of a motor vehicle, only the first sensor group with the sensors 10 and 12 , the first microcontroller 20 and the first node 28 with the first output line 32 provided. The lateral acceleration sensor 10 would then be to an input of the multiplexer 202 coupled and the in 1 with the second node 30 coupled output of the demultiplexer 206 would be with an input of the first node 28 coupled. To upgrade the system to an improved accident sensor with rollover detection could be the same board with the additional microcontroller 22 and the additional node 30 be fitted. The changed wiring according to 1 would be easy and unproblematic feasible. The corresponding other programming of the control unit would be easy to accomplish. In particular, so can the construction due to the lower required channel numbers of each microcontroller keep low costs and it is additionally achieved an improved reliability compared to two separate systems or a system with common multi-channel microcontroller for both event sensors.

2 shows a preferred embodiment of the timing of the sensor system shown above. The specific shapes and sequences of the synchronization pulses (Sync1 and Sync2) and the control pulses (CTRL1 and CTRL2) are not mandatory for the present invention. The coordination between readout of the analog sensors, their digitization and their multiplexing or demultiplexing can be optimized by the skilled person with respect to the individual case and the components used. Important for the embodiment of the invention shown is the coding on the output lines 32 . 34 that in the timing diagram of 2 is designated as DL1 and DL2. On the first output line 32 is normally encoded the signal DL1, which alternately the the transverse and longitudinal acceleration sensors 10 . 12 transmitted data assigned to the crash sensor. The period of this encoding corresponds to the distance between the sync1 pulses. On the output line 34 is coded in the timing diagram labeled DL2 signal having a twice as long period. Here, in a first half period, the lateral acceleration data of the sensor 16 and the rotation rate data of the sensor 14 and in a second half period, the vertical acceleration data of the sensor 18 and transmit a null signal. This is easily possible since the state parameters that can be used to detect a rollover event are less time-critical than the state parameters for a crash sensor system.

Naturally put those discussed in the special description and in the Figures shown embodiments only illustrative embodiments The expert is in the light of the local Revelation a wide range of possible variations given by. In particular, the present invention is not limited to the detection of crash and rollover events. Also, the principle of the present invention is more than two Expandable sensor groups.

10

Lateral acceleration sensor the crash sensor

12

Longitudinal acceleration sensor the crash sensor

14

Yaw rate sensor the rollover sensor

16

Lateral acceleration sensor the rollover sensor

18

Vertical acceleration sensor the rollover sensor

20

first microcontroller

202

Multiplexer of 20

204

A / D converter from 20

206

Demultiplexer of 20

22

second microcontroller

222

Multiplexer of 22

224

A / D converter from 22

226

Demultiplexer of 22

24

clock

28

first node

30

second node

32

first output line

34

second output line

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102006009372 A1 [0003]
• DE 10235567 A1 [0004]

Claims (9)

Sensor arrangement, in particular for an occupant protection system of a motor vehicle, comprising - a first group of sensors ( 10 . 12 ), with which a first group of state parameters can be detected, which can be used jointly by a downstream decision unit for the detection of a first event, - a first, input side with at least one sensor ( 12 ) of the first sensor group coupled digital unit ( 20 ), which processes its supplied sensor output signals and provides them as digital values for forwarding to the decision unit, characterized by - a second group of sensors ( 14 . 16 . 18 ), with which a second group of state parameters can be detected, which are jointly usable by the downstream decision unit for the detection of a second event, - a second input side with at least one sensor ( 16 . 18 ) coupled to the second sensor group digital unit that processes its supplied sensor output signals and provides for forwarding to the decision unit as digital values, wherein - at least one sensor ( 10 ) of the first sensor group with the second digital unit ( 22 ) and at least one sensor ( 14 ) of the second sensor group with the first digital unit ( 20 ), and - the digital units ( 20 . 22 ) on the output side with a first and a second node ( 28 . 30 ), the respective digital values supplied to them corresponding to a first and a second output line ( 32 . 34 ) are coupled in such a way that the first node ( 28 ) the sensors ( 10 . 12 ) of the first sensor group corresponding to digital values on the first output line ( 32 ) and the second node ( 30 ) the sensors ( 14 . 16 . 18 ) of the second sensor group corresponding to digital values on the second output line ( 34 ) merges. Sensor arrangement according to one of the preceding claims, characterized in that the first sensor group comprises a longitudinal acceleration sensor ( 12 ) for high acceleration components along the longitudinal axis of the motor vehicle and a lateral acceleration sensor ( 10 ) for high acceleration components along the transverse axis of the motor vehicle. Sensor arrangement according to one of the preceding claims, characterized in that the second sensor group is a lateral acceleration sensor ( 16 ) for low acceleration components along the transverse axis of the motor vehicle, a vertical acceleration sensor ( 18 ) for low acceleration components along the vertical axis of the motor vehicle and a yaw rate sensor ( 14 ) for rotations of the motor vehicle about an axis perpendicular to its vertical axis. Sensor arrangement according to claim 3, characterized in that the first digital unit ( 20 ) coupled sensor of the second sensor group whose rotation rate sensor ( 14 ). Sensor arrangement according to claim 2, characterized in that the with the second digital unit ( 22 ) coupled sensor of the first sensor group whose lateral acceleration sensor ( 10 ). Sensor arrangement according to one of the preceding claims, characterized in that the coding on each output line as a periodic sequence of the digital values supplied to the respective node he follows. Sensor arrangement according to claims 3 and 6, characterized in that the lateral acceleration sensor and corresponding to the vertical acceleration sensor of the second sensor group Digital values within the periodic sequence in the same time window positioned and alternating in successive periods are coded. Sensor arrangement according to one of the preceding claims, characterized in that the processing of at least some sensor output data in at least one digital unit ( 20 . 22 ) comprises a digitization of analog sensor output signals. Sensor arrangement according to one of the preceding claims, characterized in that the processing of at least some sensor output data in at least one digital unit ( 20 . 22 ) comprises a comparison with a predetermined threshold and the generation of a corresponding 1-bit digital value.